Method of fabricating a cooling chamber for a water cooler

ABSTRACT

A RELATIVELY LOW COST COOLING CHAMBER FORMED OF INNER AND OUTER CONCENTRICALLY DISPOSED CYLINDERS AND OPPOSITE END CAPS FOR THE OUTER CYLINDER, THE ENDS OF THE OUTER CYLINDER BEING FORMED TO PROVIDE SEATS WHICH MECHANICALLY HOLD THE END CAPS SO THAT A LOW TEMPERATURE BONDING MATERIAL MAY BE USED TO PROVIDE THE SEAL BETWEEN THE END CAPS AND THE OUTER CYLINDER AND WITHOUT THE HEATING OPERATION FOR EFFECTING THE BONDING AT THE ENDS DISTURBING THE BONDING OF OTHER LOW TEMPERATURE BONDING MATERIAL USED PREVIOUSLY TO BOND OTHER PARTS OF THE CHAMBER.

United States Patent [191 SllOltES 1451 June 28, 1974 [54] METHOD OFFABRICATING A COOLING 2,401,231 5/1946 Crawford 29 458 x CHAMBER FOR AWATER COOLER 2,444,833 7/1948 Lampert 29/458 2,718,583 9/1955 Noland eta1. 156/69 X [75] Inventor: Carl E- S o es, um Ohio 2,726,184 12/1955Cox et a1. 156/69 3,197,975 8/1965 B l' 29/157.3 R [73] Assgnw ga gggggfi corporat'on 3,648,477 3/1972 ssal ll e 62/394 x [22] Filed: Apr. 30,1973 Primary E.\'aminer-Charles W. Lanham Assistant Examiner-D. C.Reiley, Ill [2]] App! 356673 Attorney, Agent, or Firm-E. C. ArenzRelated US. Application Data [63] Clfntijnuatiion of Ser. No. 116,793,Feb. 19, 1971, 57 .ABSTRACT a "e I A relatively low cost cooling chamberformed of inner [52 11.8. C1 29/1s7.3 R, 29/458, 29/1510. 1, and cutcrconcentrically disposed cylindcrs and PP 165/66, 156/69 site end capsfor the outer cylinder, the ends of the 511 1111.0 B2ld 53/00 cutcrcylindcr bcing fcrmcd to P Scam which [58] Field of Search 62/66 394,395; 156/69, mechanically hold the end caps so that a low tempera-156/182 165/66 29/157 3 R, 458 ture bonding material may be used toprovide the seal DIG 1 between the end caps and the outer cylinder andwithout the heating operation for effecting the bonding at [56]References Qited the ends disturbing'the bonding of other low tempera-UNITED STATES PATENTS ture bonding material used previously to bondother parts of the chamber. 1,906,450 5/1933 Demers 165/142 l/194l.Schabacker 29/458 6 Claims, 3 Drawing Figures This is a continuation ofapplication Ser. No. 1 16,793 filed Feb. 19, I971, now abandoned. t

BACKGROUND OF THE INVENTION 1. Field of the Invention The inventionpertains to the art of water Cooling chambers for pressurized watercoolers.

2. Description of the Prior Art Water cooling chambers for pressurizedwater coolers have been made in various forms to meet designrequirements, to comply with various health codes, and to reasonablyefficiently cool water, and have a reasonable cost. Of the various formswith which I am familiar, those shown in US. Pat. Nos. 3,475,922 and3,200,848 are exemplary of chambers having some resemblance to thechamber of the present invention.

The main aim of my invention is to provide a cooling chamber whichsatisfactorily meets the design and efficiency requirements, and is lesscostly to build than those chambers with which I am familiar.

SUMMARY OF THE INVENTION In accordance with my invention, the watercooler chamber construction includes an outer substantially uniformdiameter cylinder and an inner substantially uniform diameter cylinderof shorter length than the outer cylinder, heat transfer promoting meansin the annular space defined between the inner and outer cylinders, anend cap at both the upper and lower ends of the outer cylinder, with theend caps including a circumferential flange telescopically received atthe end of the outer cylinder with cooperating means being provided atthe end of the outer cylinder and by the end cap to provide a mechanicalCapturing of the end cap by the outer cylinder. The advantage of thisarrangement is that stock copper tubes, such as are used for waste andvent lines in plumbing, may be used to provide the inner and outercylinders, with substantially all of the bonding between the partsforming the major part of the Chamber being accomplished with lowtemperature bonding material such as pure tin before the end caps areapplied. Then, the end caps, which are also pre-tinned with lowtemperature bonding material such as puretin, are mechanically capturedand heat applied to the ends of the cylinder to provide the sealing bondbetween the outer cylinder and the end caps.

In the currently preferred construction the outer cylinder is providedwith indent means about the circumference of both ends of the outercylinder to form seats for the edges of the end flanges of the caps, andthen the outer cylinder, at the extreme end edges, is rolled over orpeened to mechanically capture the end caps.

Additional features forming a part of the preferred construction of theinvention will be detailed hereinafl ter.

DRAWING DESCRIPTION FIG. I is a partly schematic, isometric view of adrinking water cooler, with a portion of the cabinet broken away toexpose some of the main interior parts;

FIG. 2 is a partly broken, vertical sectional view of the coolingchamber according to the invention;

FIG. 3 is a partly broken top view of the cooling chamber of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drinking water coolerillustrated in FIG. 1 generally includes: a cabinet 10; a coolingchamber 12 supplied with water near its top end through water tube 14and having a top-connected bubbler valve 16; a basin top 18 having adrain outlet (not shown) connected to the pre-cooling and insulateddrain pipe 20; and a refrigeration system including a compressor 22,condenser 24, and evaporator coils 26 wrapped about the exterior of thecooling chamber 12. The chamber and coils are covered with thennalinsulation (not shown) for cold retention.

The main parts of the cooling chamber 12 include an outer shell cylinder28 of substantially uniform diameter from end to end, an inner corecylinder 30 also of substantially uniform diameter and of less lengththan the shell cylinder and which is concentrically disposed within theouter shell cylinder so as to form an annular space 32 between the wallsof the cylinders, heat transfer promoting means in the form ofcorrugated fins also designated 32 and which are best seen in FIG. 3,refrigerant tube assembly formed of the tubes 26 wound helically and inpartly flattened form about the outside of the outer shell cylinder 28,an interior wall 34 and water directing tube 36 assembly secured at theupper end of the inner core cylinder 30, and top cap assembly 38, andbottom cap assembly 40, at the top and bottom, respectively, of thecooling chamber.

In assembling the chamber, the refrigerant tubes 26 are wrapped aboutthe outer shell cylinder, the fin means 32 in the form of the circularsleeve formed of the corrugated fins is inserted within the outer shellcylinder, and the inner core cylinder 30 is then inserted inside thesleeve formed of the fins and expanded by means of a plug to push thefins 32 into a tightly confined condition between the walls of thechambers so that a high degree of thermal contact between the fins andthe chamber walls is mechanically obtained. The wall 34 and waterdirecting tube 36 at the top of the Core cylinder are then installed inassembled form as shown, and the entire assembly is tin dipped to bondthe parts together with the high quality thermal contact. In accordancewith the preferred construction substantially pure tin (which is arelatively low temperature bonding material) is used in this operationto maintain a high degree of cleanliness and also to obtain the benefitof the excellent properties of pure tin as the thermal bonding material.

A feature of the construction according to the invention is the way inwhich the end caps 38 and 40 are connected to the remainder of the watercooling chamber. Near the upper end of the outer shell cylinder 28 anindented bead 42 is provided about the circumference of the cylinder.The end cap 38 includes a circumferential flange 44 dimensioned so thatthe rim of the flange will seat upon the bead when the end cap isassembled to the outer cylinder shell. Then the extreme end edge 46 ofthe outer shell cylinder is rolled over or peened to mechanicallycapture the cap 38 in its illustrated position in FIG. 2.

The upper end cap assembly also includes a brass fitting 48 which isprovided with dual passages therein, one of which serves as the inlet tothe water cooling chamber, and the other of which serves as the outletleading to the bubbler 16. The inlet passage 50 connects to the waterdirecting tube 36 through a stub tube 52 which is telescopicallyreceived within the upper flared end of the water directing tube. Theoutlet water passage 54 (FIG. 3) is open at its bottom to the interiorspace of the water chamber at the top end thereof, and is open at itstop to the base of a stainless steel nipple 56 which is screwed into theupper end of the brass fitting 48 after the cap has been assembled tothe remainder of the chamber. The water tube 14 referred to inconnection with FIG. 1 connects to the side of the inlet passage 50 asshown in FIG. 2.

Before the upper cap 38 and its associated parts are assembled to theouter shell cylinder 28, the assembly is electro-tin-plated. Then afterthe cap has been assembled to the outer cylinder and mechanicallysecured as noted, the cap assembly is heated along with the upper partof the chamber so that the various tinned surfaces will bond to eachother.

The lower cap 40 carries a drain plug fitting 56 and a hollow controlwell tube 58 which is arranged to extend vertically in the annular space32 between one pair of adjacent corrugated fins. The lower cap 40 isalso electro-tin-plated, then assembled to the chamber and mechanicallycaptured by the rolled over flange 60 holding the end cap flange 62 withits rim against the bead64 adjacent the lower end of the outer shellcylinder.

Thus it will be appreciated that both the top and end caps are securedand bonded to the chamber in essentially the same fashion. When the endcaps and ends of the chamber are heated to effect the bonding, anadditional seal of 95 percent tin solder is applied to insure 1 that allthe space between the facing surfaces to be bonded is filled and to formfillets at the chamber rim and end caps. However, since substantiallypure tin is used in the interior parts of the chamber and in pretinningthe top cap and bottom cap, a full bond between the contacting surfacesis assured and the assembly is free of contaminating oxides. Such oxideshave typically resulted from methods where brazing or heliarcing withresultant high temperatures is used in prior art arrangements forsealing an end of a water cooling chamber.

In an effort to aid in a full appreciation of the advantages of theinvention, the following is noted. By using substantially uniformdiameter cylinders in which both ends are to be ultimately capped, it ispossible to use standard stock copper tubing such as 2 and 3 inchdiameter copper tubing of the character used for waste and vent lines inordinary plumbing practice. While it would be expected that the priorart problems typically experienced in sealing ends of water coolingchambers would be doubled by an arrangement in which both ends must becapped, by using the construction according to the invention in whichsubstantially pure tin is used and all of the parts are pre-tinned, withthe end caps being mechanically captured so that requirements of highstrength bonding materials is avoided, a relatively low cost coolingchamber is obtained in which the quality of the seal in bonding and thestrength of the chamber is fully adequate for its intended purpose.

By placing the control well 58 in the annular space 32, so that in thisposition the thermal element within the well is influenced by thetemperature of both water and refrigerant, ambient temperature changesdo not unduly influence the control element. Accordingly, adequatelyuniform water temperature is obtained despite changes in ambienttemperature. Further, in connection with the control location, anotheradvantage of having the control in the annular space as distinguishedfrom either being adjacent the refrigeration tubes on the outside, or inthe center space of the water cooling chamber, is that a relatively lessexpensive control element may be used to give adequately constant watertemperature control. The difference in expense is typically due to thedifference in differential temperature at which the element causes theswitch means to be actuated between on and off positions. It is notedthat it is not new to provide a control element in such an annularspace, but it is pointed out that with the-noted construction of thewater chamber the provision of the control element in the annular spaceis easily accommodated and is compatible with the construction as awhole.

It will be seen that the water directing tube 36 is provided with acurved end which directs inlet water into the chamber toward the wall ofthe inner core cylinder. This is considered to be advantageous in thatit creates some turbulence in the inner cylinder as distinguished froman axially directed flow of the inlet water through the inner space.

It will be also appreciated from FIG. 2 that the inlet water must firstpass the length of the inner core, and then reverse direction to flow upthrough the annular space 32 in reaching the space at the top of thechamber in communication with the outlet passage 54. Thus, not only is arelatively long water circuit provided, but the water is also subjectedto the coldest part of the chamber in passing through the annular spaceand also influences the control element in the well 58.

I claim:

1. The method of making a water cooler chamber comprising:

assembling an outer, substantially-uniform-diameter,

cylinder having upper and lower open ends with an inner,coaxially-disposed, substantially-uniform diameter cylinder of shorterlength than saidouter cylinder and locating heat transfer promotingmeans in the annular space formed between said inner and outercylinders;

applying a coating of relatively low bonding temperature material to theassembly of said inner and outer cylinders and said heat transferpromoting means to bond'the parts of the assembly together;

forming a pair of end caps for closing both the upper and the lower endof said outer cylinder, and applying a coating of relatively low bondingtemperature material to both of said end caps;

fitting said end caps to the ends of said outer cylinder in telescopicrelation thereto and mechanically capturing each end cap relative tosaid outer cylinder; and

then heating said end caps and the ends of said outer cylinder to bondthe facing surfaces thereof to each other.

2. The method of claim 1 wherein:

said end caps are telescopically received within the ends of said outercylinder; and

said mechanically capturing step includes displacing the extreme endedges of said outer cylinder inwardly.

3. The method of claim 1 wherein:

said coating of relatively low bonding temperature material is appliedthe assembly by dipping said assembly in a relatively pure tin solder,and to said end caps by electro-tin-plating said caps.

4. The method of claim 2 including:

forming an indented bead near each end of said outer cylinder to serveas stops for said end caps.

5. The method of claim 1 including:

wrapping refrigerant tube means of partly flattened cross-section in ahelical array about said outer cylinder before applying said coating tosaid assembly.

6. The method of claim 1 including:

locating a barrier wall with an open ended tube projecting therethroughin the upper end of said inner cylinder in said assembly before applyingsaid coating to said assembly; and

assembling a tube to said upper end cap, with one end extendingdownwardly for subsequent connection to said tube carried by saidbarrier wall, before applying said coating to said upper end cap.

